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A189736 a(1)=3,  a(2)=2, a(n)=3*a(n-1) + 2*a(n-2) 13
3, 2, 12, 40, 144, 512, 1824, 6496, 23136, 82400, 293472, 1045216, 3722592, 13258208, 47219808, 168175840, 598967136, 2133253088, 7597693536, 27059586784, 96374147424, 343241615840, 1222473142368, 4353902658784, 15506654261088, 55227768100832 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..100

Index entries for linear recurrences with constant coefficients, signature (3, 2).

FORMULA

a(n) = 3/2*((3/2+1/2*sqrt(17))^(n-1)+(3/2-1/2*sqrt(17))^(n-1))+5/34*sqrt(17)*((3/2-1/2*sqrt(17))^(n-1)-(3/2+1/2 *sqrt(17))^(n-1)). - Paolo P. Lava, May 24 2011

G.f.: x*(3-7*x)/(1-3*x-2*x^2) - Bruno Berselli, May 24 2011

MATHEMATICA

LinearRecurrence[{3, 2}, {3, 2}, 40]

PROG

(Maxima) a[1]:3$ a[2]:2$ a[n]:=3*a[n-1]+2*a[n-2]$ makelist(a[n], n, 1, 26);  [Bruno Berselli, May 24 2011]

CROSSREFS

Cf. A000045, A000079, A105476, A159612, A080040, A135522, A103435, A189732, A189734, A189735, A189737, A189738, A189739, A189741, A189742, A189743, A189744, A189745, A189746, A189747, A189748, A189749.

Sequence in context: A086551 A254215 A007214 * A025232 A236435 A218566

Adjacent sequences:  A189733 A189734 A189735 * A189737 A189738 A189739

KEYWORD

nonn,easy

AUTHOR

Harvey P. Dale, Apr 26 2011

STATUS

approved

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Last modified October 17 19:58 EDT 2019. Contains 328128 sequences. (Running on oeis4.)